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0 <br /> REGIONAL BOARD RESPONSE (SRTCB/OCC FILE A-1634) 11 - <br /> PETITION FOR REVIEW OF WASTE DISCHARGE REQUIREMENTS <br /> ORDER NOS. R5-2004-0028 AND R5-2004-0029 <br /> CITY OF MANTECA WATER QUALITY CONTROL FACILITY <br /> Basin Plan is expressed as the dissolved concentration. By regulation(40 CFR 122.45(c)), <br /> NPDES permit limits must be expressed as total recoverable metal. Where the objective is <br /> expressed as the dissolved concentration, a chemical translator is applied to make this <br /> conversion. The chemical translator does not modify the water quality objective,but translates <br /> the site-specific dissolved form of the water quality objective to the total recoverable form. A <br /> site-specific translator for manganese has not been developed for this discharge, therefore a <br /> default translator of 1 was used in the permit to develop the effluent limitation. The Regional <br /> Board may reconsider the effluent limitation for manganese, but it needs more information to do <br /> so. If the City submits dissolved data for this constituent that demonstrates that there is no <br /> reasonable potential to exceed the Basin Plan objective, the permit can be reopened to remove <br /> the limitations based on the new information, or if reasonable potential exists, the discharger can <br /> pursue a site-specific translator study so that an appropriate total manganese effluent limitation <br /> canbe developed. This may provide the relief sought by the petitioner, but cannot be done <br /> based on current information in the record. <br /> Please refer to permit finding 48, information sheet section 9.5,permit tables 3 and 6, and the <br /> 19 March 2004 Response to Comments document(pages 5-6, 8-9 and 23-24 and 35-36, Item No. <br /> 4, Binder No. 1) for more information. <br /> NINTH BASIS: IMPROPER REQUIREMENT TO DISCHARGE ONLY ON <br /> OUTGOING TIDES <br /> Manteca requests that the State Board modify, or order the Regional Board to modify, <br /> Order No. R5-2004-0028 to remove the last sentence of Effluent Limitation B.8 and replace <br /> it with a provision that states that all discharges are restricted.to periods with positive <br /> downstream flow velocities greater than 0.5 feet per second. In the alternative, Order No. <br /> R5-2004-0028 should be modified to include a re-opener and a schedule for the City to <br /> provide information to the Regional Board to support replacing the effluent limitation with <br /> a provision linking the discharge with positive downstream flow velocities greater than 0.5 <br /> feet per second. <br /> The required discharge on out-going tide versus the proposed discharge on downstream flows of <br /> 0.5 fps was discussed in the 19 March 2004 response to comments (page 39, Item No. 4, Binder <br /> No. 1). The Environmental Impact Report for the Manteca WQCF Phase EFIV Expansion <br /> Project (draft-October 2000,final-24 May 2001) considered the chemical and thermal impacts of <br /> a discharge on out-going tides versus a continuous discharge. This information provided the <br /> basis of the requirement to discharge expanded flows only on the out-going tide. Manteca <br /> alternatively proposed a continuous discharge with a downstream flow of greater than 0.5 fps in <br /> their 5 January 2004 comments to the tentative waste discharge requirements, suggesting that this <br /> scenario was always their intention. The Regional Board did not agree that adequate technical <br />